1. Field of the Invention
This invention relates to a slider for use in a slide fastener, and more particularly to a slider for use in a slide fastener which prevents jamming of a foreign matter between fastener elements and element-guiding portions of the slider.
2. Description of the Prior Art
In a slide fastener, fastener elements secured to fastener tapes or stringers on the opposite sides are engaged or separated due to a slider moving in one direction or the other. The slide fastener is convenient for use with clothing, bags, and many other things to be closed and hence finds a wide application.
However, a slide fastener, particularly, a slider thereof suffers from jamming of a foreign matter between fastener elements and inner element-guiding portions of the slider, particularly when the elements are to be engaged with each other. This leads to a damage to the slider itself, even to a material nipped therebetween.
One of typical sliders in the prior art slide fasteners will be described with reference to FIGS. 1 and 2, hereunder,
FIG. 1 is a plan view of a slider for use in a slide fastener, and
FIG. 2 is a front view of the slider as viewed from the diverging end of the slider.
Shown at 1.sub.1 and 1.sub.2 are left-hand and right-hand fastener elements, which are secured to fastener tapes or stringers. Shown at 2 is a slider. The slider 2 has a contracted end and a diverging end. The diverging end of the slider 2 is provided with two openings which are partitioned by an interconnecting web 6. The two openings lead to two channels 2a,2a in the slider, as shown. The slider 2 consists of an upper flat portion 7, a lower flat portion 8 and an interconnecting web 6 which interconnects the upper and lower flat portions 7 and 8 together. The side edges of the upper and lower flat portions 7, 8 are formed with inturned flanges 10, 10 which guide the fastener elements passing through the slider 2. A hook 3 is attached to the slider 2 for pulling the latter, when fastener elements are to be engaged or separated. In this respect, for achieving smooth introduction of the fastener elements into the slider, there should be provided clearances X.sub.1, X.sub.2 between the inturned flanges 10 and the tails of fastener elements positioned within the slider, as well as clearances Y.sub.1 and Y.sub.2 between the inner surfaces of the flat portions 7,8 and the fastener elements 1.sub.1, 1.sub.2. In general, the clearances Y.sub.1, Y.sub.2 correspond to 10 to 20% of the height of a fastener element, while the clearances X.sub.1, X.sub.2 correspond to 25 to 40% of the length of a fastener element. The clearances X.sub.1, X.sub.2 are referred to as transverse-direction clearances, while the clearances Y.sub.1, Y.sub.2 are referred to as vertical-direction clearances. In this respect, if the aforesaid range of clearances are reduced, then there results lack of smooth sliding in fastener elements through the slider. On the other hand, the provision of the aforesaid clearances leads to jamming of a foreign matter between fastener elements and element-guiding portions of the slider, such as inturned flanges 10,10 or flat portions 7,8 of the slider.